(a) Field of the Invention
This invention relates to an ocular attachment for an endoscope, in which the endoscopic image may be split into two images by means of one in each case of several beam splitter elements arranged one beside another and displaceable transversely to the image axis, the one image being transmissible to a first camera connector along the image axis acting as a first optical axis and the other image being transmissible to a second camera connector via an image conductor along a second optical axis, and wherein the brightness of both images is adjustable by means of the beam splitter elements carried by a mount and having different divisional ratios, by virtue of the fact that one of the beam splitter elements may in each case be located in the beam path of the endoscopic image by displacing the mount.
(b) Description of the Prior Art
An ocular attachment of this nature has been disclosed more than once in patent literature. Thus the specification of EP-B No. 087033 discloses a twin observation system comprising a television camera connector in an ocular section forming a principal optical axis and a second optical axis. The observation system has a beam splitter formed by two beam splitter elements alternately pivotable into the beam path of the endoscope, which in each case have different light division ratios. This system allows for deflecting a part of the incident light out of the main optical axis and for supplying the same to the ocular section on which a photographic instrument for example may be installed. To this end, the beam splitter elements are so constructed that 50% or 70% of the incident light is supplied to the ocular section.
Moreover, the specification of DE-OS No. 27 28 419 discloses an ocular attachment devised for an endoscope, which is a component of a co-observation system, in particular of a segmental optical system, such an ocular attachment comprising a casing for a co-observer and incorporating a beam splitter for this purpose. The latter comprises two beam splitter cubes arranged side by side within the casing, which may in each case be placed alternately in the beam path of the endoscope.
In the case of these ocular attachments, the beam path branched off in each case has supplied to it an image which corresponds to the main beam path in respect of image brightness or is substantially brighter than the same, so that a documentation device, being a photographic camera for example, had been attachable in the branch beam path only. A possibility of this kind did not exist for the direct beam path since the image directed through the same was of lesser brightness only.